The Gallagher S400 Solar Electric Fence Energizer is a heavy-duty, fully portable unit built for large-scale livestock containment and wildlife exclusion operations that demand serious, self-sufficient fence power. Delivering 4.0 stored joules, the S400 is capable of powering up to 60 miles of clean fence covering approximately 280 acres under ideal conditions with proper grounding and minimal vegetation contact. Automated battery management keeps the unit running for up to two weeks without sunlight, making it a reliable choice for remote locations and off-grid setups where consistent performance is critical. The S400 offers two selectable power modes: Wildlife Mode pulses faster day and night for maximum deterrence, while Full Power Mode pulses faster during the day and slows at night to conserve battery power when animal activity is typically lower. A 360-degree T-post mounting system allows the unit to be installed on an existing fence post regardless of which direction it faces, so you can always orient the solar panel toward the sun without repositioning your fence line. A battery status indicator takes the guesswork out of power management by alerting you when the battery needs attention, and a built-in lightning protection system and water-resistant housing keep the unit operating through rain, hail, and harsh outdoor conditions. The S400 comes ready to use with a rechargeable 12V battery, solar panel, and fence lead set included. Backed by Gallagher's 3-year manufacturer's warranty and U.S.-based customer support, the S400 is a dependable, low-maintenance solution for serious large-scale fencing operations.